Acid Base Work Packet List of Things to Include

1.  Cover page with name and date - Optional to decorate

2.  Acid, Base and Neutrals article - annotated

3.  Neutralization Reactions article - annotated

4.  "Scientific Notebook"  - Test / Investigation Sheet

5.  "Scientific Notebook" - Follow Up Questions

6.  "Scientific Notebook"  Research Questions and Research (5th period - your research will be on your Follow-Up question paper)

7.  Acids and Bases -Presentation Notes

8.  Modeling Acids and Bases and Neutrals (paper with the beakers)

9.  Lab - Ocean Acidification "Saving a Dying Alaskan Bay"  WITH Conclusion page "Scientific Notebook"  Summary and Conclusion.

Acid, Base Vocabulary Review

Acid, Base, Neutral Vocabulary Review

Hydroxide ions (OH-)_    _ 1.  Bases release this into solution.

Hydrogen ions (H+) _____ 2.  Acids release this into solution.

___________Red _______ 3.  Color Acids turn Blue litmus paper.

________Blue    ________ 4.  Color Bases turn Red litmus paper.

__________Red  _______ 5.  Color of Universal pH Indicator in Vinegar (an acid).

_______Blue or Purple___ 6.  Color of Universal pH Indicator in NaOH (a base).

A neutralization reaction which forms a neutral or H2O and Salt____ 7.  This (or these) form when equal amounts of a strong acid and a strong base are added together.

_____Water    _______ 8.  Most common neutral.

Vinegar, Lemon Juice, Citric Acid, Vitamin C, Aspirin___ 9.  Common acid.

Soap, Bleach, Drain cleaner, NaOH, Sodium bicarbonate_ 10.  Common base.

__________0-6___ 11.  pH range of acids.

____________8-12 or 14_____ 12. pH range of bases.

____________7________ 13.  pH of neutrals.

Universal pH solution, cabbage juice (Base turns blue and acid turns red)______ 14.  A common indicator of acids and bases and how it works.


______________________ 15.  If you have an unknown liquid in the science class, how would
                                                you go about figuring out what it is and making the liquid safe
                                                for clean-up?  Describe the process.

Answer to #15 -   You could use litmus paper to first determine if you have an acid, base or neutral.  If it's neutral you can clean up with paper towels (and gloves).  To determine strength of an acid or a base, you need an indicator to determine exact pH.  If the indicator like universal pH solution turns red, you have an acid.  Mix with a common base like Sodium bicarbonate (NaHCO3) - baking soda to neutralize - and then clean up.  For a base, use a common acid like citric acid to neutralize and clean up.  It's always good to wear gloves.  Neutral doesn't always mean safe - chemicals can still be poisonous to us.

Neutralization

Neutralization Reactions

Name ____________________________

Date   _____

Acid-base reactions are very common. In liquid solutions, acids increase the hydrogen ion (H+) concentration. On the other hand bases increase the hydroxide ion (OH-) concentration. When an acid and a base react in a solution the H+ and OH- ions combine to form water. These ions thus "neutralize" one another:

                                   H+     +      OH-    ---->   H₂O

A neutralization reaction is when an acid and a base react to form water and a salt and involves the combination of H+ ions and OH- ions to generate water.

The neutralization of a strong acid (HCl) and strong base (NaOH) has a pH equal to 7.  (If you have equal amounts of each and they are of equal strength/concentration/Molarity.)

                     HCl    +      NaOH  ------>    H₂O    +     NaCl

The neutralization of a strong acid and weak base will have a pH of less than 7, so the solution is still ACIDIC but less acidic than it was before.  It is more neutral.

The neutralization of a strong BASE and a weak acid is similar.  The result will be closer to neutral but still a base.

                              NaOH    +    vinegar  --------->     Weak Base (pH= 8-9)

Some important neutralization reactions:

1.    We take antacid tablets like Tums to neutralize stomach acid.  The antacid usually contains NaHCO₃ which is a weak base.

2.     Also in the digestive tract, neutralization reactions are used when food is moved from the stomach to the intestines. In order for the nutrients to be absorbed through the intestinal wall, a basic environment is needed, so the pancreas produce an antacid bicarbonate to neutralize the acidic food from the stomach.

3.    Another common use is in fertilizers and control of soil pH.  Fertilizers that improve plant growth are made by neutralizing sulfuric acid (H2SO4) or nitric acid (HNO3) with ammonia gas (NH3), making ammonium sulfate or ammonium nitrate. These are salts utilized in the fertilizer.

Study Guide Acid/Base Test

Acids, Bases, and Neutrals Test

Study Guide  - Chapter 7

Vocabulary to Know

Acid

Base

Neutral

H+ ion  (Hydrogen Ion)

OH- ion  (Hydroxide Ion)

Salt

Neutralization and Neutralization Reaction

pH and pH scale

indicator

litmus paper

Concepts to Know

1.     What are the characteristics of acids, bases and neutrals?

2.     What is pH?  What is the pH of acids, bases and neutrals?  What do we use to measure or determine pH?

3.     What are examples of acids, bases and neutrals?

4.     What happens when you put acids and bases together?  What do they form?  What is a neutralization reaction?

5.     What are some common indicators of acids, bases and neutrals and how do they indicate an acid or a base – what color indicates an acid and what color indicates a base? Neutral? (examples:  Litmus paper, cabbage juice, phenol red, universal pH solution, Bromcresol purple…)

Acids and Bases Article

Acids, Bases, and Neutrals

Name ______________________________   Date __________

For thousands of years people have known that vinegar, lemon juice, and many other foods taste sour. However, it was not until a few hundred years ago that it was discovered why these things taste sour – because they are all acids.

In the seventeenth century, the Irish writer and amateur chemist Robert Boyle first labeled substances as either acids or bases (he called bases alkalies), according to the following characteristics:

Acids taste sour, are corrosive to metals, change litmus (a dye extracted from lichens) red, and become less acidic when mixed with bases.

Bases feel slippery, change litmus blue, and become less basic when mixed with acids.

While Boyle and others tried to explain why acids and bases behave the way they do, the first reasonable definition of acids and bases would not be proposed until 200 years later.

In the late 1800s, the Swedish scientist Svante Arrhenius proposed that water can dissolve many compounds by separating them into their individual ions. Arrhenius suggested that acids are compounds that contain hydrogen and can dissolve in water to release hydrogen ions into solution. For example, hydrochloric acid (HCl) dissolves in water as follows:

HCl            +   H2O  →  H+   + Cl-

Bases are substances that dissolve in water to release hydroxide ions (OH-) into solution. For example, a typical base according to the Arrhenius definition is sodium hydroxide (NaOH):

NaOH   +   H2O  →  Na+    +            OH-

Acids act like they do because all acids release H+ into solution (and all bases release OH-).

This idea, that a base can make an acid weaker, and vice versa, is called neutralization.

Neutralization

Acids release H+ into solution and bases release OH-. If we were to mix an acid and base together, the H+ ion would combine with the OH- ion to make the molecule H2O, or plain water.  Water is NEUTRAL.

H+            +            OH-            →            H2O

The neutralization reaction of an acid with a base will always produce water and a salt, as shown below:

Acid                        Base                        Water                        Salt

HCl            +            NaOH            →            H2O            +            NaCl

HBr            +            KOH            →            H2O            +            KBr

We measure the strength of acids and bases using the pH scale.

pH = -log [H+]

This means that the LOWER the pH number, the STRONGER the acid.  The higher the pH, the stronger the base (more OH-, less H+). 

The pH scale measures how acidic or basic a substance is. The pH scale ranges from 0 to 14. A pH of 7 is neutral. A pH less than 7 is acidic. A pH greater than 7 is basic. Pure water is neutral.

Acids with a low pH of around 1 are very reactive and can be dangerous. The same is true for bases of a pH near 13.

There are many strong acids and bases in nature. Many plants have acids and bases in their leaves, seeds, or even their sap. Citrus fruits like lemons and oranges have citric acid in their juice. This is what makes lemons taste so sour.

Our bodies use acids and bases too. Our stomachs use hydrochloric acid to help digest foods. This strong acid also kills bacteria and helps to keep us from getting sick. Our muscles produce lactic acid when we exercise. Also, our pancreas uses a base called an alkali to help with digestion. These are just a few examples of how the chemistry of bases and acids help our bodies function.

ACID/BASE Indicators

If you want to know if a substance is an acid, base or neutral, you need to use an acid/base indicator.  An indicator is a substance that changes color in the presence of H+ or OH-. 

Some common indicators:

LITMUS

Red litmus paper turns blue in the presence of a base. (pH = greater than 7)

Blue litmus paper turns red In the presence of an acid. (pH = less than 7)

If neither color changes, it’s a neutral. (pH = 7)

Phenol Red

Phenol red liquid is red in a neutral, yellow in an acid, and magenta in a base.

Universal pH indicator

This liquid is green in a neutral, red in an acid and blue in a base.

Purple Cabbage Juice

Cabbage juice is purple in a neutral, reddish pink in an acid, and blue to greenish yellow in a base.

 

Possible Ninth Planet Discovered in Our Solar System - No, It's Not Pluto!

CalTech scientists have found strong evidence of a large planet in the Kuiper Belt region of our solar system.  Read the NY Times article HERE.


Picture:  NY Times

Videos on Chemical Bonding and Writing Ionic Compound Names

Khan Academy Chemical Bonding (skip the section on metallic bonds):
    Ionic, covalent, and metallic bonds: Introduction to ionic, covalent, polar covalent and metallic bonds.



Naming Ionic Compounds:





I have also included notes on Ionic Compounds in the Power Point notes section on the right hand bar of this blog.